()应当由安装单位组织召开专家论证会。
A.施工专项方案
B.危险性较大的分部分项工程专项方案
C.临时用电方案
D.超过一定规模的危险性较大的分部分项工程专项方案
参考答案:D
Jack _______ the various activities offered by the summer camp and had a good time. [ ]
A. concentrated on
B. approved of
C. participated in
D. appealed to
以下不是单模光纤的非线性效应的是()
A.自相位调制SPM
B.交叉相位调制XPM
C.偏振模色散PMD
D.四波混频FWM